The present invention relates to a working device having an element movable via at least one working cylinder, with at least one energy recovery cylinder being provided for recovering energy from the movement of the movable element and having a chamber filled with gas. The present invention in this respect in particular relates to a movable working device, in particular to an excavator or to a machine for material handling.
The chamber of the energy recovery cylinder filled with gas is compressed on a lowering of the movable element in such working devices and thus stores the potential energy in order to output it again on an upward movement of the movable element to support the working hydraulic cylinder.
A working device is known from DE 10 2008 034 582 A1 in which the chamber of the energy recovery cylinder filled with gas is formed by the base side of the energy recovery cylinder filled with gas and by the hollow piston rod of the energy recovery cylinder. In this respect, a filling valve for filling the chamber filled with gas is provided and a relief valve is provided by which gas can escape on an exceeding of a preset pressure limit to avoid a bursting of the cylinder.